Non-lethal weapons, also called less-lethal weapons, less-than-lethal weapons, non-deadly weapons, compliance weapons, or pain-inducing weapons are weapons intended to be less likely to kill a living target than are conventional weapons. It is often understood that accidental, incidental, and correlative casualties are risked wherever force is applied, but non-lethal weapons try to minimize the risk as much as possible. Non-lethal weapons are used in combat situations to limit the escalation of conflict or where employment of lethal force is prohibited or undesirable or where rules of engagement require minimum casualties or policy restricts the use of conventional force.
Non-lethal weapons may be used by conventional military in a range of missions across the force continuum. They may also be used by military police, by United Nations forces, and by occupation forces for peacekeeping and stability operations. Non-lethal weapons may also be used to channelize a battlefield or control the movement of civilian populations or limit civilian access to restricted areas (as they were utilized by the U.S.M.C.'s 1st Marine Expeditionary Force in Somalia in 1995). When used by police forces domestically, similar weapons, tactics, techniques and procedures are often called “less lethal” or “less than lethal” and are employed in riot control, prisoner control, crowd control, refugee control, and self-defense.
In the past, military and police faced with undesirable escalation of conflict had few acceptable options. Military personnel guarding embassies often found themselves restricted to carrying unloaded weapons. National guards or policing forces charged with quelling riots were able to use only Batons or similar club-like weapons, or bayonet or saber charges, or fire live ammunition at crowds. In the late 1980s and early 1990s, the Non-lethality Policy Review Group at U.S. Global Strategy Council in Washington and other independent think tanks around the world called for a concerted effort to develop weapons that were more life-conserving, environmentally friendly, and fiscally responsible than weapons available at that time. The futurists Alvin Toffler and Heidi Toffler reported comprehensively on this phase of the history of non-lethal weapons in their 1993 book, War and Anti-War. The U.S. Congress and other governments agreed and began an organized development of non-lethal weapons to provide a range of options between talking and shooting.
One category of less than lethal weapons under development is sonic, acoustic psycho-acoustic weapons intended to inflict serious discomfort, pain or even light injury to persons within a target area of the weapon. These weapons are intended to generate and direct sound waves at the target area with an intensity and frequency composition known to achieve a desired discomfort/pain/damage level in persons within the area. To date, effective solutions for controllably generating and directing sufficient amounts of acoustic energy across a sufficient range of distances and spreads do not exist. There is a need for improved methods, devices apparatus, assemblies and systems for generating and directing sound pressure waves.